This invention relates to a unique positioning of an axial oil supply port for a scroll compressor.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a pair of interfitting scroll members each have a base and a generally spiral wrap extending from the base. The wraps interfit to define compression chambers. One of the two scroll members is caused to orbit relative to the other, and the interfitting wraps define compression chambers As the orbiting scroll orbits the size of the compression chambers decrease and an entrapped refrigerant is compressed.
One challenge to a scroll compressor designer is that the entrapped refrigerant creates a force tending to separate the two scroll members. In response to this xe2x80x9cseparating forcexe2x80x9d a portion of the refrigerant is tapped from a compression chamber to a back pressure chamber behind the orbiting scroll. This entrapped refrigerant creates a force tending to resist the separating force. A pair of seals are positioned within a crankcase which supports the orbiting scroll to define the back pressure chamber. Further, a coupling is typically positioned radially outwardly of the seals to constrain the orbiting scroll for orbital movement.
It is desirable to supply lubricant both to the seals and to the coupling. In the past, oil is supplied through the driveshaft into a cross-hole extending through the orbiting scroll. This oil is then delivered to a location between the seals and the coupling. In the past this oil has been delivered at a location upstream of the beginning of the orbiting scroll wrap. It is desirable that this oil not be supplied at a location where it is likely to flow into the compression chambers in undue amounts. Thus, it would be desirable to position the cross-hole at a location such that it is unlikely the oil will flow into the scroll compressor.
In the disclosed embodiment of this invention, a hole for supplying oil to a downwardly extending supply hole is positioned between 25xc2x0 and 90xc2x0 from the beginning of the orbiting scroll wrap. More preferably, this hole is positioned 30xc2x0.
With this positioning, the lubricant will be adequately supplied, but will not be likely to flow into the compression chambers in any undue amount.
More preferably, the present invention incorporates a scroll compressor wherein there are two refrigerant supply ports spaced by approximately 180xc2x0. Thus, the positioning of the supply port downstream of the beginning of the scroll wrap by a limited angular amount will ensure that that oil will not flow in undue amounts into the compression chamber through either of the suction ports. Again, this provides benefits.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.